1. Field of the Invention
The present invention relates to a structure for the self-aligning connection of a canopy for an exit sign to a mounting plate adapter for a standard wall-mounted electrical junction box. More particularly, the invention pertains to a structure constituted of a mounting plate which is adapted to be fastened to the back wall of an exit sign back cover so as to form a mounting structure adapted for facilitating the attachment of the exit sign to a wall-mounted electrical junction box, and wherein the mounting plate is adapted to be engaged by a canopy so as to be in predetermined selective orientations therewith and facilitate aligning of canopy mounting holes with the junction box in a simple and easy manner.
The utilization of exit signs which may consist of essentially rectangular box-like structures having housings with exit legends illuminated by lighting fixtures arranged in canopies interiorly of the exit sign is well known and widely employed in the particular technology. In accordance with specific demands, exit signs may be mounted on walls, wherein the rear surface or back wall of the exit sign back cover is adapted to be located in surface contact with the wall and fastened to a wall-mounted junction box, ordinarily through the intermediary of screws or other suitable fastening devices, and with electrical wires or conduits extending from the junction box to the illuminating elements which are arranged within an exit sign. Alternatively, the exit sign may also be side mounted or top mounted and; for example, suspended from a ceiling or extending outwardly at a generally angular orientation from a wall; for instance, such as at a right angle thereto.
Ordinarily, the back wall of the back cover of an exit sign housing when adapted to be essentially flush-mounted to a standard wall-mounted electrical junction box necessitates that a customer must push or punch out so-called "knockouts" formed in the back cover by means of suitable weakening lines, and which initially cover one or more potential holes which must align with mounting holes formed in the electrical junction box to facilitate the passage therethrough of fastening elements. This particular type of assembling procedure for the components is extremely time-consuming, and is at times difficult to implement even by experienced electricians or sign installers. Furthermore, in some instances, complicated mounting structure must be attached to an exit sign housing or the like, in which an exit sign canopy bracket structure is designed to be attached to an electrical junction box mounting plate and thereafter affixed thereto through the intermediary of suitable fastener devices.
The foregoing types of exit sign structures and arrangements for mounting such exit signs to junction boxes, and for readily positioning the canopy on the exit sign housing, particularly when mounting the exit sign to a standard wall-mounted electrical junction box in which the back cover of the exit sign is adapted to be essentially flush with or closely extend against the wall surface having the junction box mounted therein, has heretofore been either difficult to install, or requires structural components which are complex in nature and expensive to manufacture.
2. Discussion of the Prior Art
Johnstone, U.S. Pat. No. 5,272,605 discloses an exit sign incorporating a device comprising a canopy mounting bracket wherein, particularly for top mounting of the exit sign, the canopy bracket is temporarily fastened to an electric box mounting plate for a wall-mounted or ceiling mounted electrical junction box. Resilient or spring capture barb members on the canopy mounting bracket are engaged with the mounting plate for a junction box in order to provide at least the temporary fastening prior to the exit sign and canopy being permanently attached to the junction box. This type of structure can also be applied to side-mounted exit signs; however, it is complex in nature and difficult to align the canopy and junction box, and is not readily adapted for mounting an exit sign flush against a wall having a wall-mounted standard junction box arranged therein.
Teisen-Simony, U.S. Pat. No. 4,813,197 discloses a plate mounting system, such as for sign posting arrangements, wherein the plate elements interengage by means of suitable fastener or connecting elements. There is no disclosure of being able to mount an exit sign to a standard wall-mounted electrical junction box through the intermediary of a detachably mounted back plate fastened to the back cover of the exit sign.
Ruskouski, et al., U.S. Pat. No. 5,416,679 discloses a mounting base assembly which is employed for a lighting device installed in an exit sign. In that instance, a plurality of illuminating elements are arranged in elongate base members within electrical sockets and are constituted of light emitting diodes. Such structure can be employed in any exit sign irrespective as to the type of installation thereof, but is not concerned with the mounting of self-aligning canopies.
Lee, U.S. Pat. No. 4,263,739 discloses a bracket which is attached to the end edge of an exit sign which is adapted to extend from a wall or ceiling, and which provides a tamperproof connection to a junction box installed within the wall. As in the above-mentioned patents, there is no disclosure of a self-aligning canopy structure which is attachable to a wall-mounted junction box.